How to change the tool that will be temporarily selected by pressing Ctrl key?

I need to change the tool that will be temporarily selected by pressing Ctrl key.

The default setting is kSelectTool, and I want to kDirectSelectTool.
I have used the following code for this:
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AIAddToolData data;
data.title = ai::UnicodeString("Annotator Tool");
data.tooltip = ai::UnicodeString("Annotator Tool");
data.sameGroupAs = kNoTool;
data.sameToolsetAs = kNoTool;
data.normalIconResID = kAnnotatorToolIconResourceID;
data.darkIconResID = kAnnotatorToolIconResourceID;
data.iconType = ai::IconType::kSVG;

ai::int32 options = kToolWantsToTrackCursorOption | kToolWantsAlternateSelectionTool;
error = sAITool->GetToolNumberFromName(kAnnotatorTool, &data.sameGroupAs); 
if (error) return error;

error = sAITool->GetToolNumberFromName(kAnnotatorTool, &data.sameToolsetAs); 
if (error) return error;

if (!result) {
result = sAITool->AddTool(message->d.self, kAnnotatorTool, data, options, &fToolHandle);
}

error = sAITool->SetAlternateSelectionToolName(fToolHandle, kDirectSelectTool);

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If SetAlternateSelectionToolName writed before AddTool, error > 0.
So I write it after AddTool, and error = 0.
And I can get the name kDirectSelectTool by using 

char* name;

sAITool->GetAlternateSelectionToolName(fToolHandle, &name);
Anyway when I pressed Ctrl key, I still got Select Tool. Nothing changed.
Can anyone please suggest me that what should I do in this code?
Thanks in advance
Kuo